A mobile phone aims to provide mobile communication functions, and a personal digital assistant (PDA) aims to provide data processing and storage function. They target different requirements of users. The conventional mobile phone or PDA includes a host, which contains a circuit board and various electronic elements. On the mobile phone, the host has a display screen and a phone keypad (consisting of 0-9, #, *, receive or OFF buttons) on one side. Operation of various functions of the mobile phone is accomplished through the phone keypad. On the PDA, the host has a touch display screen and a plurality of function keys on one side. Its function is mainly accomplished through the operation of a stylus.
In recent years multimedia applications (such as games, videos, movies, music, and the like) have been integrated with the mobile phone or PDA. Under the demand of multimedia applications, vendors have introduced flip mobile phones or PDAs, such as a MOTOROLA model V600 mobile phone (reference can be found in www.motorola.com) mobile phone, NOKIA model 7270 mobile phone (reference can be found in www.nokia.com), or a SONY model PEG-UX50 PDA (reference can be found in www.sony.jp). The flip mobile phone or PDA can provide a larger display screen or other operation modes (such as including a keyboard for data entry). The flip mobile phone has a phone keypad on the host. The flipping cover contains a display screen. The flipping cover is coupled on the top end of the host through a one-way hinge for opening or folding relative to the host. Although the flipping cover can accommodate a large display screen, the one-way hinge allows the flipping cover to swivel only one way, thus limits the operation mode.
These days many new mobile phones also equip with a camera lens for taking dynamic video and still images. To provide a photo mode or other operation mode, the mobile phone with a biaxial hinge has been developed. Reference can be found in U.S. patent publication Nos. 20040110529, 20040132482, 20040192422, and 20040198474. They all provide a mobile phone equipped with a biaxial hinge. The flipping cover is pivotally coupled on the top end of the host through a biaxial hinge, to enable the flipping cover to be lifted, or the display screen to be selectively moved to face or oppose the host. While the display screen is turned with its backside folding over the host, the camera lens of the mobile phone may be used to take pictures in an operation mode like a digital camera.
With the electric products more diversified and versatile, and consumer's demands for multiple function and portability growing, electric devices that integrate the functions of mobile phone and PDA become a trend of product development. As a result, PDA phone or smart phone that equips mobile phone and data processing functions has been developed and introduced. The smart phone generally adopts the structure of mobile phone or PDA. The biaxial hinge mentioned above may also be adopted on the smart phone to provide multiple operation modes. For instance, to use the mobile phone function, the flipping cover may be lifted to use the phone keypad for dialing. To use the PDA function, the flipping cover may be swiveled with the back of the display screen folding over the host, then operation may be performed by touching the display screen with the stylus. Reference of the mobile phone or smart phone adopting a biaxial hinge can be found in U.S. patent publication Nos. 20040203527, 20040203532, 20040203535, and 20040209645.
While the smart phone that adopts the biaxial hinge allows the display screen to be swiveled and folded over the host to provide PDA operation mode, it uses a few keys and the stylus as the main input means. In order to provide a better-input mode, some smart phones adopt a design that integrates a QWERTY keyboard, such as U.S. patent publication Nos. 20040203513 and 20040204197. They mainly have a second hinge or a third hinge to couple the QWERTY keyboard on the host so that the QWERTY keyboard may be folded over or retracted in the host. In the PDA function mode, the QWERTY keyboard may be lifted or pulled out for data entry. However, such a construction has to add an extra QWERTY keyboard and makes the entire structure of the smart phone very complicated and bulky. This is not a desirable design.
U.S. patent publication No. 20040203517 also discloses a smart phone that includes a host and a display screen. The host has a QWERTY keyboard on two sides of the surface. The display screen contains a phone keypad. And the display screen is pivotally coupled on the host in the center through an one-way hinge to swivel horizontally. In the mobile phone operation mode, the display screen and the host are located in the same direction, and cover the QWERTY keyboard on one side. In the PDA operation mode, the display screen may be swiveled horizontally at 90 degrees to make the display screen normal to the host. Then users can operate the QWERTY keyboard on both sides of the host. But in the PDA operation mode, the display screen and the host are parallel. To facilitate data entry on the QWERTY keyboard, the smart phone usually is placed on a desktop, with the screen in parallel with the desktop. Users have to lower the head at a great angle to see the display screen during operating of the keyboard. This causes a great physical strain to the users.
In addition, MOTOROLA has introduced a smart phone model MPx (reference can be found in www.motorola.com). It also has a host and a flipping cover. The host has a QWERTY keyboard and a phone pad on the surface. Pivot seats are installed, respectively, on a top edge and a side edge of the host, and are adjacent to the top edge and the side edge of the host, to allow the flipping cover to be selectively coupled on the pivot seat at the top edge or the side edge. When the flipping cover is pivotally coupled on the pivot seat at the top edge, it may be lifted towards the topside to provide a mobile phone operation mode. When the flipping cover is pivotally coupled on the pivot seat at the side edge, it may be lifted towards one side to provide a PDA operation mode. In the PDA operation mode, the lifted flipping cover forms an angle with the host to allow users to place the phone on a desktop, to facilitate viewing. While it overcomes the viewing problem of U.S. patent publication 20040203517, the MPx model has to employ two pivot seats to provide two different operation modes, to perform the mobile phone or PDA function. As the QWERTY keyboard and the phone keypad are located on the host, to reduce the size, some keys are commonly shared by the QWERTY keyboard and the phone keypad, and setting and switching of the keys have to be done through a firmware to allow one key to generate different output signals. Moreover, the MPx flipping cover has a size proximate to the host. When a user wants to dial a phone number, the flipping cover has to be lifted to strike the phone keypad. On the other hand, when the MPx is functioning as a PDA, the flipping cover has to be lifted. If the user does the operation by the stylus, he will find out that doing the operation is more difficult than doing the operation by the QWERTY keyboard. U.S. Pat. No. 6,728,557 discloses a device that provides an operation mode like the MPx smart phone of MOTOROLA. It differs from the MPx by having a biaxial hinge, located on the juncture of the top edge and a side edge of the host, to pivotally couple with a flipping cover, so that the flipping cover may be lifted towards the top edge or the side edge. But the problems of the MPx still exist in the patent 557.
All the conventional techniques or cited references mentioned above, whether for mobile phone, PDA or smart phone, mostly adopt a one-way hinge or a biaxial hinge to swivel the flipping cover relative to the host to provide different operation modes. Take the smart phone that provides the functions of a mobile phone and a PDA for instance, it has to provide a mobile phone operation mode to receive calls and perform dialing, and a PDA operation mode with a QWERTY keyboard and a stylus to do data entry. They all cannot implement these diversified operation modes with a satisfactory result. There is still room for improvement.